Prolactinoma (cont.)

Robert Ferry Jr., MD

Robert Ferry Jr., MD, is a U.S. board-certified Pediatric Endocrinologist. After taking his baccalaureate degree from Yale College, receiving his doctoral degree and residency training in pediatrics at University of Texas Health Science Center at San Antonio (UTHSCSA), he completed fellowship training in pediatric endocrinology at The Children's Hospital of Philadelphia.

Ruchi Mathur, MD, FRCP(C)

Ruchi Mathur, MD, FRCP(C) is an Attending Physician with the Division of Endocrinology, Diabetes and Metabolism and Associate Director of Clinical Research, Recruitment and Phenotyping with the Center for Androgen Related Disorders, Department of Obstetrics and Gynecology at Cedars-Sinai Medical Center.

Aside from a prolactinoma, what else can cause prolactin levels to
rise?

In some people, high blood levels of prolactin can be traced to
causes other than a prolactinoma. Other causes include:

Prescription drugs: Prolactin secretion in the pituitary
is normally suppressed by the brain chemical, dopamine. Drugs that
block the effects of dopamine at the pituitary or deplete dopamine
stores in the brain may cause the pituitary to secrete prolactin.
These drugs include the major tranquilizers trifluoperazine (Stelazine) and haloperidol (Haldol); metoclopramide (Reglan)
used to treat gastroesophageal reflux and the nausea caused by
certain cancer drugs; and less often, alpha
methyldopa and
reserpine
(Harmonyl) used to control hypertension.

Other pituitary tumors: Other tumors may block the flow of dopamine from the brain, which normally inhibits its prolactin-secreting cells. Such so-called
"mixed" tumors arise in or near the pituitary, and include those that release excessive growth hormone (acromegaly) or stimulate cortisol production (Cushing's syndrome). These can also cause the pituitary to secrete more prolactin.

Some nonpituitary tumors: Prolactin secretion can also be
caused by certain cancers, such as lung cancer.

Hypothyroidism: Increased prolactin levels are often seen
in people with hypothyroidism, and doctors routinely test people with
hyperprolactinemia for hypothyroidism.

Breast stimulation can modestly increase the
amount of prolactin in the blood.

Chest wall trauma (for example, an injury from a car steering wheel after an accident) can lead to
increased levels of prolactin.

Marijuana use is also a well documented cause of elevated levels of prolactin.